Auto Transmission Kick-Down

Behind the gas peddle there's a switch.  If you depress the peddle all the way to the floor the switch is closed and the auto transmission is supposed to "kick-down" a gear or two.  It's very handy for overtaking or anywhere you'd like a quick burst of speed.

On my car, the kick-down doesn't always happen when the switch is closed.  I'd say it'll work about 50% of the time.  Sometimes I go to overtake, floor the peddle and nothing happens.

Was wondering if there's actually a fault there ?  Is this kick-down *always* supposed to happen or is it normal for it to not happen sometimes because the brain decides it's not a suitable time to shift down a gear ?

Just wondering if there's actually something wrong with it.  Bently manual says jack s**t - yet again.

Has anyone experienced this or have the low-down here ?

Thanks.

Well it's usefull to know that it's always supposed to happen anyway.

There are no obstructions to the switch or anything - I can feel the switch "switching" when I depress the pedel full - like an extra "notch" when the pedal is applied after full throttle.

I'm thinking dodgy switch then at this stage.  Must test it and see if it needs replacing.

Is the kick down cable adjusted ok, I had one on the E30- not sure on the 5.

On my old '88 E30 320i, there was a button on the floor, and a cable going to the throttle body, when I had gearbox trouble a mechanic mate removed the cable to dissengage the kickdown in an attempt to fathom out what was wrong. turned out to be the 4th gear clutch had dissintigrated.
Might be different on other models.

My E28 has the switchable auto, and seems to kick down just fine. It has the switch on the floor as expected, but no sign whatsoever of the indicated kickdown cable to the throttle body. All the manuals say it should be there but it isn't - should it be? It seems to perform perfectly well otherwise.

The EH switchable autos, both earlier 4-speed and later 5-speed had a purely electrical switched kickdown-you won't find a kickdown cable on these variants.

The earlier 4-speed autos came in both electronic switchable and non-switchable mechanical versions. You can easily tell which one's which as only the switchable box had the switch for selecting E, S or M (winter or manual) modes, along with the kickdown switch under the accelerator pedal with the wires coming from it.

Only the non-switchable boxes without the 3-mode Economy, Sport and Manual settings will have a kickdown cable running from the throttle body down to the autobox-you only have the 1 operating mode with these boxes.

All 5-speed autos were switchable and, I think, most or all E34's with the 4-speeders were switchable as well.